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From "Yu Li (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HBASE-17747) Support both weak and soft object pool
Date Tue, 07 Mar 2017 16:23:38 GMT
Yu Li created HBASE-17747:

             Summary: Support both weak and soft object pool
                 Key: HBASE-17747
                 URL: https://issues.apache.org/jira/browse/HBASE-17747
             Project: HBase
          Issue Type: Improvement
            Reporter: Yu Li
            Assignee: Yu Li

During YCSB testing on embedded mode after HBASE-17744, we found that under high read load
GC is quite severe even with offheap L2 cache. After some investigation, we found it's caused
by using weak reference for IdReadWriteLock. In embedded mode the read is so quick that the
lock might already get promoted to the old generation when the weak reference is cleared,
which causes dirty card table thus slowing YGC.

So we proposed to use soft reference for this IdReadWriteLock used in cache, which won't get
cleared until JVM memory is not enough, and could resolve the issue mentioned above. What's
more, we propose to extend the WeakObjectPool to be more generate to support both weak and
soft reference.

Note that this issue only emerges under embedded mode with DirectOperator, in which case all
costs on the wire is removed thus produces extremely high workloads.

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